Function earley_build_dynamic_matchers 

pub fn earley_build_dynamic_matchers(
    terminals: &[TerminalDef],
    g_regex_flags: u32,
    translate_python_regex: bool,
) -> Result<DynamicMatchers, FrontendError>

Eagerly build the dynamic-Earley matchers at construction, surfacing a zero-width / bad-regexp FrontendError::Grammar (Lark’s construction-time GrammarError) before any parse runs. g_regex_flags is the grammar-wide bitmask (0 for the common no-g_regex_flags grammar).